Shikantaza (Japanese 只管打坐, shikan means "only", "simply" or "merely", ta has reinforcing function (literally it means "to strike") and za is the "sitting") is usually translated into German as "just sitting". It is a meditation technique cultivated primarily in Zen Buddhism, especially as a central element of the Sōtō school.
Shikantaza refers to an important form of zazen in which introductory techniques such as counting the breath or the intensive study of koans practiced in the Rinzai school are dispensed with.
It is "zazen for the sake of zazen," although the term "zazen" in this context is not limited to the zazen posture. Zazen in this context means the undivided, holistic presence.
The most important source work describing the practice of shikantaza is the Shōbōgenzō of Dōgen Zenji (1200-1253).
Shikantaza is often referred to as the method without method. It addresses the mindset of Zen practitioners and is a deepening method of Zen meditation. Unlike other meditation techniques, there is nothing to do here but simply sit in conscious awareness.
The idea is not to think about sitting itself, but to become one with sitting there. To this end, the thoughts that soon seem to endlessly rush upon the practitioner must be let go until they gradually become less and less frequent.
By no means, however, is the goal to actively suppress the thoughts in the mind or to push them away until the mind has become "empty". Rather, the goal is to discover what lies "behind" the thoughts, if one is willing to give them up.
Unlike in a state of sleep or twilight, for example, one is in a particularly clear and present state of consciousness during the practice, which is, however, free of discursive thinking.
Shikantaza is not a detached method, but is based on the zazen posture and the basic attitude of not sticking to any experienced state or feeling. The practice is conceived as an endless deepening.
Even an enlightened person is not supposed to cling to the "state" of satori, but to leave even this experience behind and deepen the practice further.
According to the teachings of Soto Zen, the accompaniment of serious Shikantaza practitioners by an experienced (Zen) master or teacher is considered necessary in order to prevent a number of undesirable developments.
A danger in this method of meditation is sometimes seen as adherence to the practice of zazen itself, as described by Shunryū Suzuki in his book Zen Mind / Beginner's Mind.
Shikantaza and zazen practice are taught only together. Therefore, sitting without concentration and daydreaming to escape the unpleasant situation also becomes the subject of shikantaza. To stop the escape from the here and now also in the everyday life of the person is therefore also in the sense of Shikantaza.
Shikantaza as a guiding principle in Dōgen's work.
The Shōbōgenzō written by Zen Master Dōgen Zenji contains a total of four characterizing guiding principles along with Shikantaza. These guiding sentences describe the fundamentals for the practice of zazen as Dōgen describes them in his work.
Shikantaza is therefore not an isolated method, but must be considered and practiced in the overall context of the other guiding principles.
The other three are
Beyond our personal subjective thinking / thinking and doing are one. The guiding principle describes the unity of body and mind.
The regular sitting in zazen in the correct posture. The guiding principle describes the necessary regular practice and aims at the physical doing. Shinjin Datsuraku
Freeing oneself from body and mind / body and mind have fallen away. No longer attached to the body and abandoned all thoughts to experience life in its purest form.
Shikantaza as Kôan
In Steven Heine's (ed.) Dogen and Soto Zen (Oxford 2015) is the essay "Dogen's Use of Rujing's 'Just Sit' (shikan taza) and Other Koans" by T. Griffith Foulk, which the editor summarizes as follows:
"A central thesis of this chapter is that Dogen did not in fact teach (or even imagine) the kind of zazen commonly assigned to him by modern Soto scholars and Zen teachers as shikantaza. Foulk analyzes in detail that Dogen's instructions for zazen do not use this term, nor do they recommend a method that aligns with what contemporary scholars say about sitting-only."
Rather, Foulk shows that Dôgen understood "sitting-only" as kôan. Dôgen, he says, conceived of sitting in several ways, as both physical and as "mental sitting" possible in any posture.
However, if the practitioner is not attached to either physical or mental phenomena, then this liberated state is the "sitting of 'body and mind have fallen away.'" Foulk concludes that Dôgen understood his teacher Rujing's exhortation to just sit as a request in this sense: "Only attain awakening!".